MEDICATIONS AND MATHBOB WARNER, MS, RN

YOUR MISSION IF YOU CHOOSE TO ACCEPT IT

• MATH COMPETENCY SCORES NEEDED

• NUR105 85% OR BETTER

• NUR106 90% OR BETTER

• NUR205 95% OR BETTER

• NUR206 100%

Mission Possible

YOUR RESPONSIBILITY & ACCOUNTABILITY

• CALCULATE WITH CONFIDENCE, 7TH EDITION

• CHAPTERS 1 – 22, 25….1ST YEAR

• CHAPTERS 23 – 24…2ND YEAR

• ACCURATE CALCULATION OF MEDICATION

DOSAGES IS A CRITICAL AND NECESSARY SKILL

FOR NURSES. SERIOUS HARM CAN COME TO

PATIENTS FROM MATH ERRORS.

MEDICATION ROUTES INCLUDE

DECIMAL PLACE VALUEP. 29

• THE FIRST PLACE TO THE RIGHT OF THE DECIMAL IS

TENTHS.

• THE SECOND PLACE TO THE RIGHT OF THE DECIMAL IS

HUNDREDTHS.

• THE THIRD PLACE TO THE RIGHT OF THE DECIMAL IS

THOUSANDTHS.

• IN THE CALCULATION OF MEDICATION DOSAGES IT IS

NECESSARY TO CONSIDER ONLY THREE FIGURES AFTER

THE DECIMAL POINT (THOUSANDTHS) (E.G., 0.375 MG).

DECIMAL PLACE VALUEP. 29

• WHEN THERE IS NO WHOLE NUMBER BEFORE THE

DECIMAL POINT, IT IS IMPORTANT TO PLACE A ZERO IN

FRONT OF IT. THIS WILL EMPHASIZE ITS VALUE AND

PREVENT ERRORS IN INTERPRETATION.

.15…..NO 0.15….YES

• THE SOURCE OF MANY MEDICATION ERRORS IS

MISPLACEMENT OF A DECIMAL POINT OR INCORRECT

INTERPRETATION OF A DECIMAL VALUE.

NO DECIMAL POINT

• WHEN THE AMOUNT IS A WHOLE NUMBER, DO NOT USE

A DECIMAL POINT WITH TRAILING ZEROES

15.0…..NO 15….YES

• THE SOURCE OF MANY MEDICATION ERRORS IS

MISPLACEMENT OF A DECIMAL POINT OR INCORRECT

INTERPRETATION OF A DECIMAL VALUE.

ROUNDING OFF DECIMALS

P. 37

• SOME SYRINGES ARE

MARKED IN TENTHS

AND SOME, IN

HUNDREDTHS.

ROUNDING OFF DECIMALSP. 37

• TO ENSURE ACCURACY, MOST CALCULATION

PROBLEMS REQUIRE THAT YOU CARRY YOUR DIVISION AT

LEAST TWO DECIMAL PLACES (HUNDREDTHS PLACE) AND ROUND OFF

TO THE NEAREST TENTH.

ROUNDING OFF DECIMALSGUIDELINE

DO NOT ROUND UNTIL THE FINAL ANSWER STEP

EXCEPTION: FOR CALCULATING DOSAGES BASED

ON WEIGHT PROBLEMS, THE WEIGHT WILL BE

ROUNDED TO THE NEAREST TENTH DURING THE

CALCULATION PROCESS.

ROUNDING OFF DECIMALSP. 37

• TO EXPRESS AN ANSWER TO THE NEAREST

TENTH, CARRY THE DIVISION TO THE

HUNDREDTHS PLACE (TWO PLACES AFTER THE

DECIMAL). IF THE NUMBER IN THE HUNDREDTHS

PLACE IS 5 OR GREATER, ADD ONE TO THE

TENTHS PLACE. IF THE NUMBER IS LESS THAN 5,

DROP THE NUMBER TO THE RIGHT OF THE

DESIRED DECIMAL PLACE.

WHICH IS BIGGER?AND ROUNDING

• 2.001 2.01

• 0.13 0.31

• 45.9345

• 100.42

• 100.63

EQUIVALENTS

Metric Household

5 ml 1 tsp

15 ml 1 Tbs

30 ml 1 oz

1000 ml = 1 L

1 mg = 1000 mcg

1 gm = 1000 mg

1 kg = 1000 gm 2.2 lbs

CALCULATING INTAKE & OUTPUTP. 100

ABBREVIATIONSP. 151 -158

• NEED TO MEMORIZE THE MOST COMMON

ABBREVIATIONS

• P. 149 -150

• BE CAREFUL OF THE DO NOT USE & ERROR-

PRONE LISTS

• P. 151, 155 - 158

PROPORTIONSCHAPTER 14

OUTER TERMS ARE THE EXTREMES, INNER TERMS

ARE THE MEANS. THE PRODUCT OF THE MEANS

EQUALS THE PRODUCT OF THE EXTREMES

STEP 1 5 : 25 :: 10 : 50

STEP 2 5 X 50 = 25 X 10

RATIO-PROPORTIONCHAPTER 14

STEP 1 _5_ = _10_

25 50

CROSS MULTIPLY

STEP 2 5 X 50 = 25 X 10

FORMULA METHODCHAPTER 15

DESIRED X QUANTITY

HAVE

DIMENSIONAL ANALYSISCHAP. 16

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AYER_EMBEDDED#!

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IV FLOW RATE: ML/HOURP. 536

AMOUNT OF SOLUTION (ML)

TIME IN HOURS = ML/HOUR

IV TUBING

IV FLOW RATE: GTTS/MINP. 543

AMOUNT OF SOLUTION (ML) X DROP FACTOR

TIME IN MINUTES = GTTS/MIN

LET’S DO SOME MATH PROBLEMS

ORDER: LOPRESSOR 25 MG B.I.D.

AVAILABLE: LOPRESSOR 50 MG/TABLET

ORDER: COUMADIN 7.5 MG PO DAILY

AVAILABLE: COUMADIN 5 MG/TABLET

ORDER: PENICILLIN 750,000 UNITS IV STAT

AVAILABLE: PENICILLIN 1,000,000 UNITS/10 ML

ORDER: KANAMYCIN 300 MG IM

DIRECTIONS ON LABEL: ADD 2.7 ML STERILE WATER = 1 G/3 ML

ORDER: BENADRYL 30 MG PO EVERY 6 HOURS PRN

AVAILABLE: BENADRYL 12.5 MG/5 ML

ORDER: HYDROCHLOROTHIAZIDE 0.05 G

AVAILABLE: HYDROCHLOROTHIAZIDE 25 MG/TABLET

INFUSE 1 L NORMAL SALINE (NS) IN 8 HOURS.

HOW MANY ML/HR?

INFUSE 1,000 ML NS IN 8 HOURS. DROP FACTOR IS

20 GTT/ML.

HOW MANY GTTS/MIN?